Substrate water availability on canola seeds physiological quality with different water content

Several studies have been conducted with different substances to simulate negative osmotic potentials, once the water absorption by seeds is very important to start the germination process. Thus, this work aimed to evaluate the effect of different substrate water availability on canola seeds physiological quality with different water contents. It was used the HYOLA 433 hybrid seeds, with 5.5, 7.1 and 11% of water content, submitted the following water availability in the substrate moistured with simulated aqueous solutions of polyethylene glycol (PEG 6000): 0.0, -0, 1, -0.2 -0.3, -0.4, -0.6 MPa. The seeds were sown on two "germitest" papers placed inside plastic boxes "gerbox" and maintained at 25 degrees C under white constant light. The seeds physiological quality was evaluated through the first count, germination, hypocotyl and primary root length and seedlings dry weight. The experimental design was completely randomized factorial 6 x 3 (substrate water availability and water content of seeds x), with four replications of 50 seeds for each repetition, the data being submitted to regression analysis. The reduction of substrate water to -0.3 MPa reduced the seeds germination and seedlings performance. The Brassica napus seeds are sensitive to water potential reduction of up -0,2 MPa which reduces the seeds germination and vigour.